1. Field of Invention
The present invention relates to a composite pressure vessel and, more particularly, to a method for making a rubber liner of a composite pressure vessel.
2. Related Prior Art
To make a composite pressure vessel with a rubber liner, two conventional methods are applied. In the first method, water-soluble adhesive being dissolved in water and alcohol, is mixed with sand at a predetermined ratio. The mixture is poured into a mold and made compact. The mixture is baked and cured to form a sand mold. The profile of the sand mold is lathed before it is coated with release paper. Then, a vacuum-bag process, a hand layup method or a filament winding method is executed to provide a composite on the release paper. The sand mold is dissolved in water and removed before rubber is poured onto the composite while the composite is rotated so that the rubber is vulcanized and molded at the room temperature.
In the second method, a sand mold is made and lathed before it is coated with release paper. Rubber sheet are laminated on the release paper before it is heated, pressed and molded in an autoclave. Then, the molded rubber sheet is lathed and turned into a rubber liner. Then, a vacuum-bag process, a hand layup method or a filament winding method is executed to provide a composite on the rubber liner before it is baked and cured. Finally, the sand mold is dissolved in water and removed. Thus, a composite pressure vessel is provided with a rubber liner.
In both of the conventional methods, the filament must be wound along a predetermined path to provide a designated strength to enable the composite pressure vessel to stand a designed value of pressure. In addition, to provide a precise size, the sand mold or the molded rubber must be lathed precisely, and this takes a lot of time and costs a lot of money. Moreover, the sand mold is dissolved in water and removed, and this is a waste. In the first conventional method, the thickness of the rubber liner is uneven because the rubber is poured onto the composite and vulcanized while the composite is spun
The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.